Whereas control IL6+/+;Eμ-myc mice developed lethal lymphomas with the expected latency [mean survival 103+/-46 days] and full penetrance [100% tumor incidence], the loss of IL-6 significantly delayed lymphomagenesis, extending tumor-free survival by 40% [164+/-99 days, p = 0.0031]. The gene discussed is IL6; the disease is lymphoma.